Punching die

ABSTRACT

A punching die wherein a strip steel cutting knife having the desired endless or closed configuration of patterns to be cut or punched from sheet material, is attached to a plate which is surrounded by the knife as by a frame. In one embodiment a spacing is provided between the plate facing wall of the knife and the plate all around the plate. In another embodiment the plate facing wall of the knife is provided with a groove to receive the edge of the plate.

United States Patent Inventor Ernst Spengler Heusenstamm near Offenbach, Germany Appl. No. 796,646 Filed Jan. 30, 1969 Patented Mar. 16, 1971 Assignee Roeder & Spengler OHG Bergen-Enkheim Hessen, Germany Priority Feb.3, 1968, July 17, 1968 Germany R36850 and P 17 60 899.0

PUNCHING DIE 19 Claims, 9 Drawing Figs.

U.S. Cl 83/128,

76/107, 83/681, 83/682, 83/698 Int. Cl 826d 7/06,

Field of Search 83/681 Primary Examiner-Frank T. Yost Att0rney-Wolfgang G. Fasse ABSTRACT: A punching die wherein a strip steel cutting knife having the desired endless or closed configuration of patterns to be cut or punched from sheet material, is attached to a plate which is surrounded by the knife as by a frame. In

one embodiment a spacing is provided between the plate facing wall of the knife and the plate all around the plate. In another embodiment the plate facing wall of the knife is provided with a groove to receive the edge of the plate.

Patented Mrch 16, 1971 "3 Sheets-Sheet 2 7/ Zr/In VII;

Patented March 16, 1-971 3 Sheets-Sheet 5 PUNCIIING DIE It is the purpose of the present invention to provide improvements of known punching dies having a strip steel knife closed to a specific shape and being held on a base plate.

Up to now a strip steel knife was connected rigidly and undetachably with an exactly cutout base plate.

Such punching dies are thrown away after their use as they can be altered only with great difficulties and a reuse is not possible. If only slight modifications are to be made to a style, a new base plate must be cut and possibly a new knife must be shaped. In this way high expenses are caused. It is an object of the present invention to avoid such drawbacks.

The invention uses perforated strip steel to which holding angles are fastened which extend into the space surrounded by the configuration of the strip steel knife, for connection to a base or inner plate by further fastening means which whereby a clearance or spacing is provided between the plate and the strip steel knife.

According to the invention, the base plate need not be out exactly since the plate does not have, to correspond precisely to the exactly shaped strip steel knife due to said clearance which makes possible small modifications to the form by removing a holding angle, bending the strip steel knife in the new shape and fixing it by fastening a new holding angle. These features are facilitated by the fact that the strip steel is prepunched or perforated.

In order that the invention may be clearly understood it will not be described, by way of example, with reference to the accompanying drawings, wherein:

FIG. I a is a planview of a punching die according to the invention;

' FIG. 2 is a section through a holding angle;

FIG. 3 is a plan view of a holding angle;

FIG. 4 is a section similar to FIG. 2 of a further embodiment;

FIG. 5 shows the fastening of a cutting-in knife on the strip steel knife;

FIG. 6 is a section similar to FIG. 2 of a further embodiment; FIG. 7 is a partial view similar to FIG. I for another embodiment; I

FIG. 8 is a representation similar to FIG. 4 for the embodiment according to FIG. 7; and

FIG. 9 is a section through the strip steel for the embodiment according to FIGS. 7 and 8.

FIG. I shows a plan view of a punching die for a sleeve part.

A strip steel length 1 provided along its full length with perforations in the form of a single or double hole row is bent to a closed or endless configuration corresponding to a pattern, for example, a sleeve pattern.

At some of the perforations holding angles 2 are fastened, e.g. by screws or by riveting, with so-called pop rivets 5 or the like.

In some zones so-called cutting-in knives 3 or other marking tools, such as taper plugs or hollow punches, are fastened to the strip steel knife I, by means of sheet metal holders 3a with screws or rivets 5 (FIG. 5).

The flange 4 of each holding angle 2 protruding towards the interior is provided, as is shown by FIGS. 2 and 3 with punched-out and bent upward lugs in the form of barbs 6.

For providing the die with bodily rigidity, a base plate 7 is inserted and the barbs 6 are driven into the base plate.

All around the base plate 7 between the outer edge thereof and a plate facing wall of the strip steel knife 1, there is pro vided a spacing or clearance 8.

' Suction cups 9 or magnetic holders or the like are attached to the bottom of the base plate 7. An ejector means 10 is provided on the side of the base plate facing in the direction of the cutting edge. The purpose of the cups or holders9 is to hold the stamping die on a stamping apparatus.

A punching die according to the invention. can also be used for cutting mirror-inverted shapes, if the strip steel 11 has two opposed cutting edges as shown in FIGS. 4m 9.

U-shaped holding angles 12 are fastened to the strip steel 11 e.g. by means of rivets 15 extending through the perforations. The profile legs 14 of the holding angles 12 protrude inwardly and grip around the baseplate 7 FIGS. 4 or 6. These profile legs have aligned perforations to receive rivets 18 or screws or the like.

FIG. 6 shows a further embodiment in which an essentially U-shaped holding angle 12 is connected similarly to the embodiment according to FIG. 4 ona knife 1 sharpened only at one edge.

The holding angles are suitably profiled to make them more rigid (FIG. 3).

The cutting-in knives3 can also be fastened to the base plate instead of being fastened to the strip steel knife I, so that their position is independent of the perforation of the strip, (cf. FIG. 1).

In the embodiment according to FIG. 7, the base or inner plate 27 has a configuration which rests practically without any clearance inside the knife of the die. The strip steel knife 21 is provided on its inner or plate facing surface with a groove 22 extending in parallel to its cutting-edge (FIG. 9).

The width of the groove 22 corresponds approximately to the thickness of the base plate 27. The depth of the groove corresponds to the thickness of the inner level of the cutting edge. The peripheral edge of the base plate 27 extends into the groove 22 when the punching die is finished. The outline of the pattern forming the base plate 27 coincides thus with the shape formed by the cutting edge 23 a and 23b, respectively.

If the strip steel 21 is smooth on both sides, i.e. if it does not have a groove 22, the outline of the pattern forming the base plate 27 must be smaller by the thickness of the inner level or taper of the cutting edge in case of the strip steel knife according to FIG. 9 thus by half the thickness of the strip steel 21. Then the cutting line 23a or 23b corresponds to the desired shape of the workpiece if the strip steel 21 engages the base plate 27 snugly.

The material of the pattern forming the base plate 27 can be of any type. The pattern may consist, e.g. of cardboard of ;a thickness of 2 to 3 mm., plastics material, wood, thin metal, transparent material or a material with any outlines.

In the embodiment of FIGS. 7 and 8 the base plate 27 has a lower resistance to buckling than in the first embodiment. Therefore, the holding angles 212 serve for holding the strip steel 21 during the stamping exactly perpendicularly to the base plate 27. For this purpose the holding angles 212 are provided with a sufficiently large back surface 213 which rests on the plate facing side of the strip steel knife 21 (FIG. 8).

In order to be able to fasten the base plate 27 to the holding angle 212 so that the plate is held between the legs 214, e.g. by rivets 218, the base plate 27 is provided within the range of each holding clamp 212 with suitably semicircular recesses 271.

As in the embodiment according to FIG. 4, the holding clamps 212 of FIGS. 7 and 8 are connected with their wide upper web to the strip steel knife 21 by means of rivets 215.

In order to facilitate the manipulation of the punching die particularly when lying on the material to be punched out, the base plate may be provided with rectangular recesses 272 corresponding to a thread path or--if the plate 27 is made of transparent material--with markings corresponding to the thread path.

The gist of the second embodiment of the invention is to ob tain with the same simple and cheap holding means as in the first embodiment an exactly shaped pattern made of relatively thin, but sufficiently resistant material placed directly into a punching die.

The invention is not limited to the embodiments described. Details can be adapted to the purposes according to the particular circumstances without departing from the scope of the invention as defined by the appended claims.

Iclaim:

I. In a punching die for cutting predetermined patterns out of sheet material, wherein a strip steel knife blade having a plate facing wall of given width and a cutting edge forming a closed configuration corresponding to said pattern, is attached to an inner plate having a given thickness, by means for rigidly securing the knife blade to the plate, the improvement comprising: a groove in said plate facing wall of said knife blade, said groove having such a depth that the groove extends between the plate facing wall of the knife blade and a plane extending through the cutting edge in parallel to said plate facing wall, said groove having a width corresponding substantially to the thickness of said plate, said groove extending in a plane defined by said plate so that the plate extends into the groove.

2. The punching die according to claim 1, wherein said securing means are holding angles which are riveted to the knife blade as well as to the inner plate.

3. The punching die according to claim 1, wherein said innner plate has a plurality of recesses in its peripheral area, and wherein said securing means comprise rivet means and brackets having two spaced arms interconnected adjacent to said plate facing wall by a crosspiece having a sufficiently large back surface corresponding in-its length substantially to said given width of said plate facing wall, said spaced arms having aligned apertures through which said rivet means extend, said large back surface also having an aperture through which rivet means extend, said securing means being located at least with said crosspieces in said recesses.

4. The punching die according to claim 1, wherein said securing means are holding angles comprising a knife facing leg and a plate facing leg, and barbs secured to said plate facing leg for entering into said plate.

5. The punching die according to claim 1, further comprising cutting-in members and means for securing said cutting-in members to the plate facing wall of the knife blades.

6. The punching die according to claim 1, further comprising ejector means held on said plate on the side facing in the direction of said cutting edge.

7. The punching die according to claim 1, further comprising holding means secured to said plate for attaching the die to a punching apparatus.

8. The punching die according to claim 1, wherein said knife blade is provided with two opposed cutting edges whereby said plane extends through both cutting edges.

9. The punching die according to claim 1, wherein said inner plate is made of transparent material.

10. The punching die according to claim 1, further comprising marking means in said inner plate.

1]. In a punching die for cutting predetermined patterns out of sheet material, wherein a strip steel knife blade having a plate facing wall having a given width, a cutting edge forming a closed configuration corresponding to said pattern, is attached to an inner plate having an outer edge by means for rigidly securing the knife blade to the plate, the improvement comprising a spacing between the outer edge of said inner plate and said plate facing wall of the knife blade, said spacing extending all around the inner plate, said securing means comprising leg portions of sufficient length to bridge said spacing.

12. The punching die according to claim 11, wherein said securing means are holding angles which are riveted to the knife blade as well as to the inner plate.

13. The punching die according to claim 11, wherein said securing means are holding angles comprising a knife facing leg and a plate facing leg, and barbs secured to said plate facing leg for entering into said plate.

14. The punching die according to claim 11, further comprising cutting-in members and means for securing said cutting-in members to the plate facing wall of the knife blades.

15. The punching die according to claim 11, further comprising ejector means held on said plate on the side facing in the direction of said cutting edge.

16. The punching die according to claim 11, further comprising holding means secured to said plate for attaching the die to a punching apparatus.

17. The punching die according to claim 11, wherein said knife blade is provided with two opposed cuttin ed es.

18. The punching die according to claim 1 wfierein said inner plate is made of transparent material.

19. The punching die according to claim 11, further comprising marking means in said inner plate. 

1. In a punching die for cutting predetermined patterns out of sheet material, wherein a strip steel knife blade having a plate facing wall of given width and a cutting edge forming a closed configuration corresponding to said pattern, is attached to an inner plate having a given thickness, by means for rigidly securing the knife blade to the plate, the improvement comprising: a groove in said plate facing wall of said knife blade, said groove having such a depth that the groove extends between the plate facing wall of the knife blade and a plane extending through the cutting edge in parallel to said plate facing wall, said groove having a width corresponding substantially to the thickness of said plate, said groove extending in a plane defined by said plate so that the plate extends into the groove.
 2. The punching die according to claim 1, wherein said securing means are holding angles which are riveted to the knife blade as well as to the inner plate.
 3. The punching die according to claim 1, wherein said innner plate has a plurality of recesses in its peripheral area, and wherein said securing means comprise rivet means and brackets having two spaced arms interconnected adjacent to said plate facing wall by a crosspiece having a sufficiently large back surface corresponding in its length substantially to said given width of said plate facing wall, said spaced arms having aligned apertures through which said rivet means extend, said large back surface also having an aperture through which rivet means extend, said securing means being located at least with said crosspieces in said recesses.
 4. The punching die according to claim 1, wherein said securing means are holding angles comprising a knife facing leg and a plate facing leg, and barbs secured to said plate facing leg for entering into said plate.
 5. The punching die according to claim 1, further comprising cutting-in members and means for securing said cutting-in members to the plate facing wall of the knife blades.
 6. The punching die according to claim 1, further comprising ejector means held on said plate on the side facing in the direction of said cutting edge.
 7. The punching die according to claim 1, further comprising holding means secured to said plate for attaching the die to a punching apparatus.
 8. The punching die according to claim 1, wherein said knife blade is provided with two opposed cutting edges whereby said plane extends through both cutting edges.
 9. The punching die according to claim 1, wherein said inner plate is made of transparent material.
 10. The punching die according to claim 1, further comprising marking means in said inner plate.
 11. In a punching die for cutting predetermined patterns out of sheet material, wherein a strip steel knife blade having a plate facing wall having a given width, a cutting edge forming a closed configuration corresponding to said pattern, is attached to an inner plate having an outer edge by means for rigidlY securing the knife blade to the plate, the improvement comprising a spacing between the outer edge of said inner plate and said plate facing wall of the knife blade, said spacing extending all around the inner plate, said securing means comprising leg portions of sufficient length to bridge said spacing.
 12. The punching die according to claim 11, wherein said securing means are holding angles which are riveted to the knife blade as well as to the inner plate.
 13. The punching die according to claim 11, wherein said securing means are holding angles comprising a knife facing leg and a plate facing leg, and barbs secured to said plate facing leg for entering into said plate.
 14. The punching die according to claim 11, further comprising cutting-in members and means for securing said cutting-in members to the plate facing wall of the knife blades.
 15. The punching die according to claim 11, further comprising ejector means held on said plate on the side facing in the direction of said cutting edge.
 16. The punching die according to claim 11, further comprising holding means secured to said plate for attaching the die to a punching apparatus.
 17. The punching die according to claim 11, wherein said knife blade is provided with two opposed cutting edges.
 18. The punching die according to claim 11, wherein said inner plate is made of transparent material.
 19. The punching die according to claim 11, further comprising marking means in said inner plate. 